For the closing mechanism and ramming means on artillery pieces and the like it is previously known to achieve speed controlled movements of a screw breech mechanism or a ramming car with the aid of a so-called constant flow valve and a controlling cam profile means. For the known arrangement it has then been proposed to utilize four non-return valves arranged in a bridge connection which ensure that operating flow through the valve can be conducted in the same direction through the valve during both directions of movement of the piston.
The known arrangement has required a comparatively large space on the firearm, and, therefore there has been a need for equipment which requires less space. Requirements continuously remain within weapons development for simplified function and design of the various parts of the weapons.